netdev - Re: [PATCH][bpf-next] bpf: change bpf_skb_generic

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 3 Jan 2020 09:27:13 +0100
From:   Simon Horman <simon.horman@...ronome.com>
To:     Li RongQing <lirongqing@...du.com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: Re: [PATCH][bpf-next] bpf: change bpf_skb_generic_push type as void

On Fri, Jan 03, 2020 at 02:02:33PM +0800, Li RongQing wrote:
> bpf_skb_generic_push always returns 0, not need to check
> its return, so change its type as void
> 
> Signed-off-by: Li RongQing <lirongqing@...du.com>

Reviewed-by: Simon Horman <simon.horman@...ronome.com>

> ---
>  net/core/filter.c | 30 ++++++++++--------------------
>  1 file changed, 10 insertions(+), 20 deletions(-)
> 
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 42fd17c48c5f..1cbac34a4e11 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c

...

> @@ -5144,7 +5134,7 @@ BPF_CALL_3(bpf_lwt_seg6_adjust_srh, struct sk_buff *, skb, u32, offset,
>  		if (unlikely(ret < 0))
>  			return ret;
>  
> -		ret = bpf_skb_net_hdr_push(skb, offset, len);
> +		bpf_skb_net_hdr_push(skb, offset, len);

There is a check for (ret < 0) just below this if block.
That is ok becuase in order to get to here (ret < 0) must
be true as per the check a few lines above.

So I think this is ok although the asymmetry with the else arm
of this if statement is not ideal IMHO.

>  	} else {
>  		ret = bpf_skb_net_hdr_pop(skb, offset, -1 * len);
>  	}
> -- 
> 2.16.2
>